1. Field of Invention
The invention relates to a washable cover for mattresses or similar objects, made from textile material and comprising a water vapor permeable, allergen- and waterproof barrier layer, and an outer material. The invention also relates to a mattress with such a washable cover.
2. Description of Related Art
The suitability of waterproof, water vapor permeable membranes or sheeting for mattress covers is known in the art as exemplified in EP 0 761 715 A1 and DE 43 39 475 A1. In this way, the portion of the perspiration given off by the user and unable to escape into the environment or the covering blanket can be directed into the mattress core, which then gives off the moisture into the environment when the mattress is not in use. It has been noted that, in one night, an average of about 400 ml of perspiration is given off by the mattress user, and about a third of this perspiration must be absorbed by the mattress core in order to provide a comfortable climate for the user. Since a large portion of the perspiration is present in vapor form in the air surrounding the user, this vapor can also enter the mattress core through these membranes or sheeting. The waterproof quality of these membranes or sheeting is of increased importance because on the one hand penetration of perspiration in the form of liquid into the mattress core is effectively prevented, and on the other hand bodily fluids such as blood or urine, which would soil the mattress core and also serve as a breeding ground for the allergens, also cannot penetrate into the mattress core.
In this manner, soiling of the mattress core, which provides a breeding ground for allergens, is avoided effectively. The mattress cover must then be removed regularly from the mattress and washed to remove bodily secretions, which also serve as a breeding ground for allergens, from the cover.
It is also known that such membranes or sheeting can be impermeable to allergens, i.e., impermeable to mites, bacteria, or other microorganisms or solid particles, which can also be in gaseous form and have a adverse effect on the body, as exemplified in EP 714 950 A2, WO 96/21379 and DE 40 27 798. In this case, a portion of the perspiration given off by the user in the form of vapor is directed in turn to the mattress core, while penetration of the allergens present in the perspiration, and other bodily fluids, is avoided.
On the other hand, statements are often made in the art that such membranes or sheeting do not exhibit adequate strength and that these membranes or sheeting must therefore be reinforced by additional textile fabrics. For this reason, such membranes or sheeting are generally in the form of laminates, whereby the membranes or sheeting are often laminated only pointwise to the textile fabrics providing reinforcement, in order to enable permeability for water vapor. Such membranes or sheeting are exemplified in WO 96/21379, WO 94/19178, WO 93/14929, WO 90/00969, EP 0 732 073 A1, EP 0 622 488 A1, DE 195 22 333 A1, DE 40 27 798 A1, DE 38 35 016 A1 and NL 9200790.
While the structures of washable mattress covers described up to now are effective in creating a comfortable climate for the user, they do not offer sufficient comfort when the user is reclining, since the membranes or sheeting known in the art are used only to produce thin covers, and padding between the mattress core and outer material of the cover has not been employed. Such padding, which should be composed of a voluminous, textile material, generally tends to form lumps, so that the padding can be used only if it is quilted (sewn) to the other fabrics in order to prevent displacement of the padding and formation of lumps. Quilting is not possible with waterproof membranes or sheeting, however, because the membranes would thereby lose their waterproofing qualities.